Parallel 类并行任务（仅仅当执行耗时操作时，才有必要使用）

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            Stopwatch sw = new Stopwatch();
            sw.Start();

            ////非并行任务，总耗时间：3000
            //Thread.Sleep(1000);
            //Thread.Sleep(2000);

            ////并行任务，总耗时间：2000
            //Parallel.Invoke(() =>
            //{
            //    Thread.Sleep(1000);
            //}, () =>
            //{
            //    Thread.Sleep(2000);
            //});


            List<int> list = new List<int>();
            var len = 0;
            object _olock = new object();
            var count = 0; //用户计算大于5000数的个数
            for (int i = 0; i < 10000; i++)
            {
                list.Add(i);
            }
            len = list.Count;

            Parallel.For(1, len, (i) =>
            {
                lock (_olock)
                {
                    //耗时操作
                    Thread.Sleep(1);
                    if (i > 5000)
                    {
                        count++;
                    }
                }
            });


            sw.Stop();
            Console.WriteLine(sw.ElapsedMilliseconds);

            Console.Read();
        }
    }
}

 参考博客：https://www.cnblogs.com/ricky-wang/p/7003162.html